Although this is the second appearance of Speedy Gonzales (his first outing was in Gatos e Explosivos não se Mistiram (1953)), he was re-designed after his debut and this is the first appearance of Speedy as we know him today.
This cartoon is the first time Speedy Gonzales and Sylvester meet.
The saguaro cactus seen in the opening shots establish the location of the border as the Sonoran Desert, where the tall Cactaceae family members are native. That would place the action in the far southeast of California or in neighboring southern Arizona.
In this short, WB's vendor of choice, Acme, has entered the cheese manufacturing business. But later in the cartoon, it seems to have changed its name to Ajax, another popular WB vendor.